利用水溶性幾丁聚醣以薄膜過濾法去除微量之金屬離子

Use of water-soluble chitosan for the removal of metal ions from dilute solutions by membrane filtration

蕭瑞昌(Reuy-Chang Hsiau)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(1996年)

摘要

本論文是研究水溶性聚電解質-幾丁聚醣(Chitosan)之醋酸溶液與微量
重金屬離子在均勻相(Homogeneous phase)中形成錯合物，利用錯合-超過
濾(Complexation-ultrafiltration，UF )程序來去除金屬離子。首先測
定純幾丁聚醣之理化性質及其透過液流率，並測定純金屬離子之透過液流
率及其去除率關係，以了解各物質對薄膜反應性及去除效果。進而，改變
薄膜材質、孔徑大小、操作壓力、溶液pH值及溶液進料濃度比，來測定此
系統去除率及透過液流率關係，由此可知系統之最佳操作條件。接著，利
用化學平衡與質量平衡，由理論模式可得幾丁聚醣(S)與氫離子(H'')之平
衡常數(Ke)，金屬離子(M2+)與幾丁聚醣(S)之結合常數(Kd'')及平均結合
計量常數(n)。並由透過液之流速變化，可測得修正結垢指數(Modified
fouling index)，以了解超過濾的結垢現象。

關鍵字

超過濾 ； 幾丁聚醣

並列摘要

In this paper, a complexation(ultrafiltration (UF) process was
proposed to check the feasibility for removing metal ion from
dilute solution after their complexation with water(soluble
polymers (polyelectrolytes) in homogeneous phase. The
polyeletrolytes was chitosan which is a weak base. The physical
and chemical properties such as solubility, degree of
deacetylation, molecular weight for chitosan with acetic acid
aqueous were measured. The UF flux and rejection coefficient
were measured for the system of S/M2+ by changing parameters
such as membrane material, pore size, the applied pressure, the
aqueous pH, and the concentration ratio. In the instance, the
optimal removal conditions were obtained. The equilibrium
constants of S(H'' (Ke''), S(M2+ (Kd'') and average stoichiometric
number (n) from the relation between the aqueous pH and
rejection coefficient were calculated according to the chemical
model which was based on the reaction mechanism using mass
balance. Finally, the fouling of membrane during UF process was
identified by the modified fouling index（MFI）from flux data.

並列關鍵字

Superfiltration ； Chitosan